I'm using a RS-485 board at a non-standard baud rate of 250 kbaud (each serial word is about 44 microseconds long). I'm sending five bytes (serial words) at a time. My problem is I'm getting a variable gap time between each serial word that varies anywhere from 10 and 40 microseconds. It looks like the VISA software is sending the data bytes one at a time and that the variable gap time is an interrupt or DMA response time. I tried changing all the serial attributes that looked remotely related to this with no effect. I'm not doing anything fancy like using multiple threads or asynchronous operations. Does anyone know how I can reduce the gap time between serial data words to near zero?
Have you tried changing your FIFO settings to match the number of bytes you are transmitting? If the number of bytes are constant this should help cut down the time gap. The FIFO can be changed in MAX if it is an NI board or in the Windows Device Manager for most other boards. Repost if this does not help.
